Recessing tool



H. J. PFREHM RECESSING TOOL Dec. 28, 1948.

Filed Jan. 26, 1946 Patented Dec. 2, 1948 This invention relates to a recessing tool.

An object of the invention is to provide a tool of the character described specially adapted to form annular inside recesses in a bore which is designed to receive the end of a tube.

When the end of the tube is inserted into the recessed bore said end is expanded by internal pressure into the recesses and is thereby anchored in place.

It is another object of the present invention to provide a recessing tool having novel means for expanding the cutters when inserted into the bore.

It is a further object of the invention to provide a tool of the character described having means for automatically retracting the cutters, when the recesses have been completed, for withdrawal from the bore.

The invention also embodies an adjustable spacer for locating the cutters at the selected place in the bore.

With the above and other objects in view the invention has particular relation to certain novel features of construction, arrangement of parts and use, an example of which is given in this specification and illustrated in the accompanying drawings, wherein:

Figure l is a plan View of the tool.

Figure 2 is a side View, partly in section, taken on the line 2-2 of Figure l, as applied to the work, and

Figure 3 is a cross sectional view taken on the line 33 of Figure 2.

Referring now more particularly to the drawings wherein like numerals of reference designate the same parts in each of the figures, the numeral l designates the shank of the tool which is adapted to be fitted into the machine spindle 2. Extended forwardly from the shank there is the cutter expander 3 which is of a general cylindrical shape and which is reduced in diameter forming the eXternaI annular shoulder 4.

The cutter expander is provided with a deep lengthwise groove 5 which extends substantially throughout the length thereof and whose bottom is formed into an outwardly tapering face 6, which extends to the free end of the cutter expander.

Mounted on the face 6 to move longitudinally relative to the groove 5 there is an elongated cutter carrier 1. That portion of the expander in front of the carrier 1 has been cut away to provide the clear space 8 in front of the cutters.

Slidably mounted on the expander 3 there is a tubular bushing 9 forming an anchor and surx 2,457,2t9 g niacnssmsrrh'on i Harry J. Pfreh mjfiouston, I r l 4 i I Application "January 26, 1946, "SerialNo. 4 2574 7 ailaim. (or. 77-58) rounding the expander there is a coil sprin III which is interposed between said anchor and the shoulder 4. Within said bushing there is a longitudinal slot H in the expander of slightly less length than the length of the bushing and a key l2 has a threaded connection with the bushing with its inner end projecting into the slot, or keyway, H.

The cutter carrier is provided with a transverse groove l3 and located within the slot 5 and anchored, at one end, to the inner side of the bushing 9 there is a flexible arm l4 whose other end is free and is provided with a transverse catch 15 which fits into the slot l3. There is a tubular spacer l6, one end of which surrounds the bushing 9 and whose other end is inwardly thickened and is provided to abut the work I! to space the cutter, or cutters, 19, at the desired location in the bore 20. The cutters are forwardly pitched and may be formed integrally with the carrier 1.

The end of the spacer which surrounds the bushing 9 is provided with longitudinal slots 2|, 2| and clamp screws 22, are fitted through the slots and screwed into the bushing 9, and their outer ends have enlarged heads which .clamp against the spacer so as to hold it in a fixed position when adjusted.

In applying the tool to the work the spacer should first be adjusted so that the end of the expander and the cutter will enter the bore 20 the required distance, and the clamp screws 22 tightened to maintain said adjustment. The arm M will normally hold the cutter carrier retracted, as shown in Figure 2. When the tool is thus adjusted, relative to the work, it is rotated by the spindle of the machine and as rotated the expander is gradually moved inwardly but the cutter carrier 1 is held stationary, that is against inward movement and the tapering face 6 will gradually move the cutter carrier outwardly and the cutters I9 will form annular inside grooves in the work.

As the grooves are being cut the spring II) will be gradually placed under compression. When the work has been completed the expander will be gradually withdrawn, or moved outwardly,

but the compression of the spring I0 acting against the bushing 9 will hold the cutter carrier against outward movement until the cutters l9 have cleared the grooves formed by them and the tool may then be withdrawn.

The drawings and description are illustrative merely while the broad principle of the invention will be defined by the appended claim.

the expander, a coil spring around the expander and anchored at one end to said anchorand whose other end is formed with a catch which projects into said transverse groove, a tubular "one end of which abuts the outer end of; the-an 'chor, said expander having a longitudinal keyway within the anchor, a key on the anchor'extended' f'into the keyway, a flexible arm within said slot spacer sleeve one end of which surrounds said anchor and is provided with longitudinal slots and whose other end is inwardly thickened and provided to abut the work, clamp screws extended through said longitudinal slots and having a threaded connection with the anchor whereby said tubular spacer may be adjusted relative to the anchor and fixed at any selected point of adjustment.

1 HARRY J. PFREHM.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,449,475 Wheeler Mar. 27, 1923 2,333,935 Jones Nov. 9, 1943 20 2,380,627 Zempel July 31, 1945 

